Changes in Sewage Sludge Chemical Signatures During a COVID‐19 Community Lockdown, Part 1: Traffic, Drugs, Mental Health, and Disinfectants

Abstract

The early months of the COVID‐19 pandemic and the associated shutdowns disrupted many aspects of daily life and thus caused changes in the use and disposal of many types of chemicals. While records of sales, prescriptions, drug overdoses, and so forth provide data about specific chemical uses during this time, wastewater and sewage sludge analysis can provide a more comprehensive overview of chemical changes within a region. We analyzed primary sludge from a wastewater‐treatment plant in Connecticut, USA, collected March 19 to June 30, 2020. This time period encompassed the first wave of the pandemic, the initial statewide stay at home order, and the first phase of reopening. We used liquid chromatography–high‐resolution mass spectrometry and targeted and suspect screening strategies to identify 78 chemicals of interest, which included pharmaceuticals, illicit drugs, disinfectants, ultraviolet (UV) filters, and others. We analyzed trends over time for the identified chemicals using linear trend analyses and multivariate comparisons ( p < 0.05). We found trends related directly to the pandemic (e.g., hydroxychloroquine, a drug publicized for its potential to treat COVID‐19, had elevated concentrations in the week following the implementation of the US Emergency Use Authorization), as well as evidence for seasonal changes in chemical use (e.g., increases for three UV‐filter compounds). Though wastewater surveillance during the pandemic has largely focused on measuring severe acute respiratory syndrome–coronavirus‐2 RNA concentrations, chemical analysis can also show trends that are important for revealing the public and environmental health effects of the pandemic. Environ Toxicol Chem 2021;00:1–14. © 2021 SETAC

Changes in Sewage Sludge Chemical Signatures During a COVID‐19 Community Lockdown, Part 2: Nontargeted Analysis of Sludge and Evaluation with COVID‐19 Metrics

“…All Spearman's correlation results are provided in Supporting Information, Table S12 . Overall, our findings relating sludge chemicals and SARS‐CoV‐2 RNA levels are similar to the trends found for changes in chemical levels in sludge samples over time that are presented in Part 1 (Nason et al, 2021 ). This makes sense because, for the daily sampling analysis (March 19–April 15), SARS‐CoV‐2 RNA levels increased nearly linearly, as did several of the identified chemicals.…”

“…None of the positively correlated compounds showed the characteristic hump during the first 4 weeks. Several of the negatively correlated compounds (benzotriazole, caffeine, and oxybenzone) decreased in the initial weeks before increasing for the remainder of the sampling period (Nason et al, 2021 ). These trends are likely due to pandemic‐related lifestyle changes in driving, sleeping, and cosmetic use.…”

“…All sample collection and instrumental analysis methods have been described previously (Nason et al, 2021 ; Peccia et al, 2020 ), and all method details and quality control information are provided in the Supporting Information. Briefly, primary sewage sludge samples were collected at the East Shore Water Pollution Abatement Facility, New Haven, Connecticut, USA, daily from March 19 to June 30, 2020.…”

“…The Compound Discoverer method used a peak picking algorithm that was independent of any databases or libraries and then used ddMS2 data for analyzed peaks to identify compounds using spectral match scores with compounds in the mzCloud database. Both methods used a 5 ppm mass window for mass‐to‐charge ratio values, and each identified compound was assigned a confidence level that corresponds to the software used and the certainty of the match (1 = confirmed with standard, 2 = probable identification, 3 = tentative identification; Nason et al, 2021 ; Schymanski et al, 2014 ). For further data analysis, we formed a list of all identified compounds and their concentration (targeted compounds) or peak area (suspect screening results) in each of the analyzed samples (Supporting Information, Tables S8 and S9 ).…”

“…Z. Wang et al, 2021 ). In Part 1 of this series, we used both targeted and suspect screening approaches with liquid chromatography—high resolution mass spectrometry (LC‐HRMS) to identify chemicals of interest in primary sewage sludge samples collected over the first 15 weeks of the COVID‐19 pandemic in New Haven, Connecticut, USA, and investigated trends over time during the initial lockdown and reopening phases (Nason et al, 2021 ). However, this initial study used only a fraction of the data collected with LC‐HRMS analysis and did not evaluate the relationship of detected chemicals in sludge with levels of SARS‐CoV‐2 RNA that were measured in the same environmental samples or other COVID‐19 metrics (Peccia et al, 2020 ).…”